Miniature relay



Sept. 12, 1961 2,999,916

C. HUETTEN EI'AL MINIATURE RELAY 2 Sheets-Sheet 1 Filed Sept. 11, 1959 42 i F/GZZ ITTQ /VEY Sept. 12, 1961 c. HUETTEN ETAL MINIATURE RELAY 2 Sheets-Sheet 2 Filed Sept. 11, 1959 W E M75 M E 2 m k a .2 v N 2 2 2 &

armature. "the permanent magnet repels the armature while the elec- United States Patent 2,999,916 MINIATURE RELAY "Clarence Huetten, Howard R. Reeve, and Charles R. Renter, Indianapolis, Ind., assignors to P. R. Mallory & Co., Inc., Indianapolis, Ind., a corporation of Delaware Filed Sept. 11, 1959, Ser. No. 839,400 4 Claims. (Cl. 200-93) This invention relates generally to electromagnetic zswitches and more particularly to microminiature relays capable of being hermetically sealed and used in printed circuits and the like.

Relays utilizing permanent magnets to establish coil polarization for special purpose applications are known in the art. However, up to now, a miniature relay -iutilizing a permanent magnet to replace the springs that zrequire individual and exacting mechanical adjustments.

"When these relays must operate through a wide range of :ambient temperatures, these adjustments become critical--particularly in multiple-pole units. Under conditions of vibration, springs may, unless carefully designed and adjusted, resonate within the range of vibrational frequencies to which the relay may be subjected.

Miniature relays are diflicult to seal hermetically and are usually not suitable for dust seals of conformal coatings. This requires that dust-tight containers be provided for application in printed-circuit integrations that are normally conformally coated. Once the units are sealed, hermetically or otherwise, no minor deviations or adjustments in operating voltage, operate time, etc. can normally be made without breaking the seal, mechanically readjusting the contacts, and rescaling.

Most relays, miniature or otherwise, are not suited for printed-circuit application without accessory hardware, nor are they usually suited for automatic assembly. The present invention of a sub-miniature relay otfers a simplicity of design, a minimum number of parts with many of these parts performing multiple functions. It further provides an assembly suitable for conformally coated dust seals or for hermetic seals. The present relay may be externally calibrated because it employs a permanent magnet to provide the holding force for a normally closed contact.

Several other advantages occur from the construction of the relay. Relatively low operating power is required since, to activate the relay, the electromagnet needs only to reverse the polarity of the armature until the magnetic intensity in the armature balances the magnetic intensity of the permanent magnet. At the instant that the intensities are balanced, there is no restraining force on the With further increase in armature intensity,

tromagnet attracts it. Further, high speed operation is attained inasmuch as there is no restraining force applied during the period that the armature is in motion. Inasmuch as it is only necessary to magnetize and stabilize the magnet to the desired holding force that establishes the operating characteristics, the only mechanical adjustment is the initial placement of the magnet and related parts. No additional mechanical adjustments are required for high temperature operation because a magnet can be stabilized to operate at any reasonable maximum temperature by initially cycling it to that temperature. In addition, the elimination of springs results in improved vibrational characteristics. Minor deviations and/ or adjustments in operating characteristics can be made electromagnetically and automatically on either hermetic or dust sealed units without disturbing the seal. The relay contact and coil terminals may be readily spaced to fit grid systems used on printed circuit boards designed for automatic assembly, and can be mounted, either sealed or unsealed, to a printed circuit board without accessory hardware. These mountings can be made individually or in groupings inasmuch as the relay unit may be considered modular.

It is therefore an object of the present invention to provide an improved electromagnetic relay of the springless type.

Another object of the present invention is to provide an electromagnetic relay having few mechanical parts and wherein the armature operates between poles without the use of springs.

Still another object of the present invention is to provide an improved micro-miniature relay in which minimum mechanical adjustments are necessary, and which can be made swiftly, easily and precisely.

Still another object of the present invention is to provide in a micro-miniature relay, permanent magnet means to eliminate the springs formerly used to establish the holding force of normally closed contacts.

Yet another object of the present invention is to provide a micro-miniature relay having a novel armature construction and which is adapted for use in a hermetically sealed relay for printed circuit applications.

Still another object of the present invention is to provide a micro-miniature relay requiring relatively low operating power.

These and other objects of the invention will become apparent from the specification taken in conjunction with the drawings; in which FIG. l, is a vertical cross-sectional view of the improved micro-miniature relay of the invention, as taken along line 11 of FIG. 2

FIG. 2 is a horizontal cross-sectional view of the relay invention as taken along line 22 of FIG. 1 with the container and insulator tops thereof omitted.

FIG. 3 is an exploded view of the invention showing in perspective the arrangement of the various parts of the micro-miniature relay; and FIG. 4 is a view of the invention as taken along line 44 of FIG. 2.

. is overcome by the magnetic pull generated and the armature is allowed to move upon a fulcrum provided for it. The ferromagnetic is placed internally of the coil and situated in the axially extending space therein on a fulcrum. It remains in a normally closed position by reason of the continuous magnetic field excited by the permanent magnet portion of the relay. When energy is provided to the adjacent electro-magnetic section the magnetic field is modified and the armature rocked to a second position. The relay may be completely hermetically sealed, and should adjustments be necessary, these may be made externally without disturbing the seal.

Referring now to the drawings, there are shown in FIGS. 1 and 3, the micro-miniature relay 10, comprising a coil 11, a molded coil bobbin 12A and B, a permanent magnet pole-piece with integral terminal and base boss 13, an electromagnet pole-piece with integral terminal 3 and base boss 14, an armature base with integral terminal 15, an armature 16, two coil terminals 17, 18, and insulation 19, spring clamp 20, casing 21, and base header 7 With the exception of the permanent magnet pole-piece the coil terminals, all metal parts i.e., the armature, armature base, electromagnetic pole-piece, and pole-piece terminals and bosses are made of soft magnetic material. parts, excluding the coil and coil bobbin, are plated -with good contact material such as silver, gold, platinum, palladium, rhenium, etc. All parts of the relay, with the :exception of the coil terminals, serve multiple functions. The plating, mentioned previously, acts as contact surfaces as well as protection for the base metal. It also reduces, because of the added 'air gap, the residual flux inherent at fixed and working gaps of electromagnetic circuits minimizing any holding force on the armature when the electromagnet circuit is opened during a switching operation. The armature serves as'a contact and magnetic circuit member for both the electromagnet and perinanent magnet circuits. The armature base performs as a magnetic circuit member, a terminal, and as a support and guide for the armature. Both the permanent magnet and electric magnet pole-pieces 30, 31, respectively function as magnetic circuit m'er'nbers,'conta'cts, and terminals; to- "gether, they also provide the relay base. The bobbin, s'ection 12-A, 12-B, inaddition to retaining the coil, provide locating and/ or nesting means for all metal parts. A rectangular cavity 32, open throughout the length of the bobbin core, receives and locates the armature base 15, and the armature 16. The outside wall of this bobbin core provides locating and nesting geometry for the inner coil terminal while the lower bobbin flange provides a "ne'st'forthe outer coil terminal. Both bobbin flanges re- 'ceive"and locate the two U-shaped pole-pieces, FIG. 2. Shoulders on the 'top flange 34, 35, mate with the "shoulders on the pole-piece's36, 37, to establish the work- "ing gap 38. Insulation, in addition to protecting the electric magnet and permanent magnet pole-pieces from the armature base, provides the fixed gaps.

m This relay is adaptable to two methods of assembly. For hermetically sealed units, which require a container, "the pole-pieces can be retained on the bobbin by a spring 20, compressed between 'the container 21, and a thin Teflon insulator 19, wrapped over the relay (FIG. N0. 1), or the pole-pieces can'be bonded to the bobbin.

For unsealed units (FIG. No. '2), or for conformally coated dust-sealed units, a bonded assembly is essential. Because the armature base is a snug-fit in the rectangular cavity through the bobbin core, it is retained in position, without bonding, regardless of the assembly method used. The armature is' held in position in the bond seat 'or fulcrum 40, provided on the armature base by the magnetic force applied 'by either the electromagnet or permanent magnet, whichever is activated. Coil terminals are retained by the compressive force applied by the "tightly wound coil.

Operation In the normal position, the armature 16, is attracted to the permanent magnet pole-piece 13, to provide normally closed contacts between the armature base 15, and

permanent magnet pole-piece terminals, while the contacts between the electric magnet pole-piece and the armature base terminals are normally open. When suffi- 'cient voltage is'applied across the coil terminals, the resulting magnet-motive .force reverses the polarity .of the armature and overcomes theholding force of the permanent magnet. This reversal of polarity causes the armature to be repelled from the permanent magnet polepiece and attracted to the electric magnet pole-piece. This closes the normally open contacts and opens the normally closed contacts.

It will be thus appreciated that the present invention provides an improved micro-miniature relay of compact and simple construction in which many advanced features are incorporated. These features eliminate cumbersome biasing or tensioning devices making the relay especially adapted for hermetic sealing and printed circuit applications. The simplicity and reliability of the construction adapt the relay for mass production and automated techniques heretofore prohibitive with structure of 'such extremely small dimensions. While preferred embodiments of the invention have been illustrated, the-spirit of the .in-

vention and the scope thereof will be defined by the appended claims.

What is claimed is:

1. A relay comprising, in :combination, an .insulative coil form having an axial passage therethrough and winding of wire therearound, a pair of ferromagnetic plates extending inoppositedirections .fromsaid passage, zone of said plates 'beingfixed-in and substantially fillingout to portion of the lengthof'said passage and to iother-of .said p'lates having. its inner edge mounted. for rocking: displacement on.the inneredge of the-first.plate'andiconstitutes the armature of the relay, a O-shaped permanent -magnet' member and-a Ceshaped ferromagnetic member Ifaced into each around *said'coil form :and .definingjair gaps between their ends atthe respective'ends rofzsaid passage, the endsof said C-shaped membersiat the outer end of said armature constituting stationary contact -means selectively .engageable with. said end .of the:armature when said windingsrare: energized and .1 de-energized, respectively,.a terminal pinrsecured to each: endoftsaid windings, to each ofisaid C.shaped members-and to said i fixed: ferromagnetic 1 plate constituting. mechanical mounting and. electrical: connection therefor, an .insulative; base platehaving apertures therein through which said-iterminal pins. mayt-extend: for: connection to external ener- "gizingand work circuits,.a casingslipped over said '0- 45 shaped members and saidbase plate" and constituting with said base plate arsealedenclosurefor the'relay, and

2. The relay'claimed in claim lin which the saidferro- 'magnetic plates: and 1 said: stationary contact means 1 are coated with a contact metal.

-3. The relay claimed in claim 1 in .whichan insulating layer is interposed betweenthe resilient elements andthe 'C-shaped members.

4. The relay claimedin' claim 1 in which the adjacent regions of the base plate and the casings and the terminal pins are sealed together by means of a bondingmaterial to hermeticallyseal-the relay from the exterior.

References Cited in the file of this patent UNITED STATES PATENTS 684,378 Potter Oct. 8, 1901 2,539,547 Mossman et a1. Ian. 30,v 1951 2,830,152, .Tasker etal. Apr. 8,. 1958 

